Adjustable friction hinge



FIG. 1 is a perspective view of the adjustable friction hinge embodying my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a bottom view thereof. 

The ornamental design for an adjustable friction hinge, as shown. 